1. Field of the Invention
The present invention relates to communication cables, and in particular relates to a methods for simulating the effects of routing a copper cable and determining any structural distortions and/or deterioration resulting therefrom.
2. Description of the Related Art
Network and communication equipment is often physically arranged according to specific configuration requirements. Communication cables, that carry signals to and from such equipment, may be required to be routed along one or more relatively sharp curves, according to the configuration and constraints of the setting, such as the shape and size of a chassis or drawer. Such routing can put tension on the outside sheath of the cable, and result in distortion and degradation of the various wires within the cable. One type of distortion is referred to as “micro-pistoning.”
FIG. 1, is schematic illustration depicting aspects of micro-pistoning. In FIG. 1, a cable 100, having a sheath 101 and two sub-cables 102, 104, each in turn having two conductors, is bent into a U-type shape. As shown, the bending has caused the end of sub-cable 102 to protrude upwards relative to the end of sub-cable 104 on the left side, and conversely, the end of sub-cable 104 protrudes upwards relative to the end of sub-cable 102 on the right side. If, for example, the bend occurred when one of the ends was soldered, or otherwise fixed to equipment, it can be seen that such relative movement can alter or damage the structural integrity of such a connection, and possibly cause signal transport discontinuity.
Testing of cables according to known standards such as the SFF 8417 standard (Small Form Factor Committee “Multi Conductor Cable Flex Cycle Test Procedure”) involves determining whether particular points of a tensioned cable break when flexed angularly back and forth over a set number of repetitions. Such tests do not provide a good guide as to whether a cable will perform adequately when routed as described above, and in particular, do not provide any indication of any possible micro-pistoning behavior of the cable.
What is needed is a test that provides useful information for indicating whether a communication cable will perform adequately under prevailing routing conditions, and in particular provides information indicating whether micro-pistoning or other structural distortions have occurred, which hitherto have not been subject to rigorous testing.